The present invention relates to grommets. More particularly, this invention relates to acoustic grommets for use in passing a wire bundle through a panel which separates two compartments, wherein the grommet prevents noise and water from being passed through the grommet and the wire bundle.
A grommet is typically used on a wire harness or bundle to prevent water intrusion from an environmentally exposed area (e.g., engine compartment in a vehicle) to an environmentally controlled area (e.g., inside of a vehicle). In addition to preventing water intrusion, grommets for use in the current automotive market need to have the flexibility and ability to perform two additional functions. First, grommets are increasingly required to dampen noise intrusion through the grommet. Second, grommets need to be capable of allowing additional wire content after the vehicle is manufactured, i.e., aftermarket applications. This latter function needs to be accomplished without compromising the first function, i.e., noise reduction.
Grommets which are said to provide both waterproofing and soundproofing benefits in automobiles are disclosed, e.g., in U.S. Pat. Nos. 4,685,173; 4,797,513; 4,959,509; 5,270,487; and 5,981,877. A grommet assembly which is designed to allow both a main wire harness and an auxiliary wire harness to pass therethrough is described in U.S. Pat. No. 4,959,509.
Conventional grommets which contain air or acoustic chambers either use a two-part design or do not allow for secondary (aftermarket) applications.
A primary object of this invention is to provide a watertight grommet having sound-dampening characteristics, wherein the grommet is a one-piece structure containing an acoustic chamber and means for allowing for secondary (aftermarket) applications.
A further object of this invention is to provide the grommet of the preceding object wherein the grommet allows for secondary applications without sacrificing the sound-dampening characteristics of the grommet.
Another object of this invention is to provide the grommet of the preceding objects, wherein the grommet is cost-effective.
These and other objects are achieved in the present invention.
The present invention provides a cost-effective one-piece grommet that prevents water intrusion, has sound dampening properties and further has the ability to add aftermarket applications without compromising the sealing and/or acoustic performance of the grommet.
Broadly, the one-piece grommet of this invention contains:
a hollow main body having a front opening, a back opening, and central primary passageway extending between the front and back openings, the central primary passageway being disposed for receipt of a primary wire, wire harness or wire bundle;
an annular body surrounding a portion of the main body and being spaced from and integrally joined to the main body, the annular body having a cylindrical hollow central portion, a front flange portion, an acoustic chamber formed in the front flange portion, an intermediate flange portion, a back flange portion, and an annular panel-fitting groove formed between the intermediate and back flange portions;
a secondary passageway formed between the inner wall of the annular body and the main body, the secondary passageway being disposed for receipt of at least one auxiliary wire and being spaced inwardly from the acoustic chamber and the annular panel-fitting groove and outwardly from the primary passageway such that the secondary passageway does not pass through the acoustic chamber, the annular panel-fitting groove or the primary passageway; and
a back annular rim section defined between the back opening of the main body and the inner wall of the annular body, the annular rim section having formed therein one or more through-holes and one or more protruding members having removable ends and covering the one or more through-holes, the one or more through-holes and the one or more protruding members being disposed in communication with the secondary passageway.
In the grommet of this invention, the means for allowing auxiliary wire(s) or wire bundle(s) to be added after the grommet has been installed (i.e., the secondary passageway and the corresponding through-holes and protruding members formed in the annular rim section) does not compromise the sound dampening properties of the grommet because the secondary passageway does not pass through the acoustic chamber. In addition, the secondary passageway does not pass through the primary passageway of the main body and, therefore, does not compromise any sealant which may be applied to the primary passageway or the primary wire harness. Furthermore, the secondary passageway does not compromise the sealing of the grommet to a panel because the passageway does not pass through or otherwise interfere with the annular panel-fitting groove.
The grommet of this invention is particularly suitable for use in the automotive industry, where the grommet would typically be attached to a firewall located between the engine compartment and the passenger compartment.